diff --git a/main.rkt b/main.rkt
index 2b6593a..8edeb8f 100644
--- a/main.rkt
+++ b/main.rkt
@@ -14,6 +14,7 @@
                     any)]
   [clear-coverage! (-> any)]
   [get-test-coverage (-> coverage/c)]
+  [irrelevant-submodules (parameter/c (or/c #f (listof symbol?)))]
   [make-covered?
    (-> file-coverage/c path-string?
        (->* (exact-positive-integer?)
diff --git a/private/format-utils.rkt b/private/format-utils.rkt
index fcc16e8..ad9fec4 100644
--- a/private/format-utils.rkt
+++ b/private/format-utils.rkt
@@ -1,5 +1,5 @@
 #lang racket/base
-(provide make-covered?)
+(provide make-covered? irrelevant-submodules)
 (require racket/file
          racket/function
          racket/list
@@ -26,7 +26,8 @@
 ;; A Covered? is a [Nat [#:byte? Boolean] -> Cover]
 
 ;; FileCoverage PathString #:ignored-submods (maybe (listof symbol)) -> Covered?
-(define (make-covered? c path #:ignored-submods [submods #f])
+(define (make-covered? c path)
+  (define submods (irrelevant-submodules))
   (define vec
     (list->vector (string->list (file->string path))))
   (define file/byte->str-offset (make-byte->str-offset vec))
@@ -36,8 +37,10 @@
     (hash-ref file-location-coverage-cache (if (not byte?) loc (- loc (file/byte->str-offset loc)))
               'missing)))
 
+;; (or/c #f (listof symbol))
+(define irrelevant-submodules (make-parameter #f))
 
-;; Path FileCoverage OffsetFunc -> [Hashof Natural Cover]
+;; Path FileCoverage -> [Hashof Natural Cover]
 ;; build a hash caching coverage info for that file
 (define (coverage-cache-file f c submods)
   (vprintf "caching coverage info for ~s\n" f)
diff --git a/scribblings/api.scrbl b/scribblings/api.scrbl
index 8fe5776..0711b0c 100644
--- a/scribblings/api.scrbl
+++ b/scribblings/api.scrbl
@@ -46,18 +46,23 @@ coverage information for that file @racket[make-covered?] returns
 a functions that determines if some @racket[1] indexed character or byte location
 in that file is covered. By default it checks character locations.
 
-There are three possible results:
-@itemize[@item{@racket['irrelevant] --- The location is not considered relevant to coverage information.
-It is either not in the coverage information; is in a submodule; is a @racket[begin-for-syntax] form;
-or lexes (in the sense of that languages, @racket[_color-lexer]) as a comment or whitespace.}
-@item{@racket['covered] --- The location is not @racket['irrelevant] and is
-covered}
-@item{@racket['uncovered] --- The location is not @racket['uncovered]
-and is not covered}]
-                                   }
+There are three possible results: @itemize[@item{@racket['irrelevant] --- The location is not
+considered relevant to coverage information.  It is either not in the coverage information; is in a
+submodule specified by @racket[irrelevant-submodules]; is a @racket[begin-for-syntax] form; or lexes
+(in the sense of that languages, @racket[_color-lexer]) as a comment or whitespace.}
+@item{@racket['covered] --- The location is not @racket['irrelevant] and is covered}
+@item{@racket['uncovered] --- The location is not @racket['uncovered] and is not covered}] }
+
+@defthing[irrelevant-submodules (parameter/c (or/c #f (listof symbol?)))]{
+
+A parameter that controls with submodules are considered irrelevant by @racket[make-covered?]. It
+defaults to @racket[#f], which tells @racket[make-covered?] to consider all submodules
+irrelevant. If its value is a list, then each element of that list is the name of a submodule to be
+considered irrelevant.}
 
 @deftogether[(@defproc[(generate-coveralls-coverage (c coverage/c) (p path-string? "coverage")) any]
               @defproc[(generate-html-coverage (c coverage/c) (p path-string? "coverage")) any])]{
-Generates coverage information in the coveralls and html
-formats. Equivalent to the specifications of the @Flag{c} argument to
-@exec{raco cover}.}
+
+Generates coverage information in the coveralls and html formats. Equivalent to the specifications
+of the @Flag{c} argument to @exec{raco cover}. Both use @racket[make-covered?] to determine file
+coverage.}
diff --git a/tests/main.rkt b/tests/main.rkt
index dd0fcc4..1466805 100644
--- a/tests/main.rkt
+++ b/tests/main.rkt
@@ -3,7 +3,7 @@
 ;; for every .rkt file in those directories it loads
 ;; tests that file and checks its coverage against an
 ;; .rktl file of the same name
-(require (only-in "../main.rkt" test-files! clear-coverage! get-test-coverage)
+(require (only-in "../main.rkt" test-files! clear-coverage! get-test-coverage irrelevant-submodules)
          "../private/file-utils.rkt"
          racket/runtime-path rackunit)
 
@@ -65,7 +65,10 @@
 
 (module+ test
   (define-runtime-path-list test-dirs '("basic" "simple-multi" "syntax"))
-  (for-each (compose test-dir path->string) test-dirs))
+  (for-each (compose test-dir path->string) test-dirs)
+  (define-runtime-path submods "submods")
+  (parameterize ([irrelevant-submodules null])
+    (test-dir (path->string submods))))
 
 (module+ test
   (define-runtime-path prog.rkt "prog.rkt")
diff --git a/tests/submods/prog.rkt b/tests/submods/prog.rkt
new file mode 100644
index 0000000..dab3972
--- /dev/null
+++ b/tests/submods/prog.rkt
@@ -0,0 +1,2 @@
+#lang racket
+(module+ test (+ 1 2))
diff --git a/tests/submods/prog.rktl b/tests/submods/prog.rktl
new file mode 100644
index 0000000..01ea0dc
--- /dev/null
+++ b/tests/submods/prog.rktl
@@ -0,0 +1,2 @@
+((1 35))
+()